Exercise training reduces ventricular arrhythmias through restoring calcium handling and sympathetic tone in myocardial infarction mice

The benefits of exercise on heart failure after myocardial infarction (MI) have been well established, while the underlying mechanisms remain to be fully investigated. Our study showed that continuous intensive exercise training can suppress ventricular arrhythmias in subacute to chronic phase of MI through restoring autonomic imbalance and impaired calcium handling, similarly to that for β‐blockers. In addition, we suggested a novel possible mechanism that the antiarrhythmic effects of exercise or β‐blocker treatment are, at least in part, attributed to regulations of miR‐1‐mediated PP2A activity and its downstream targets, hyperphosphorylated CaMKII‐RyR2, in MI. AbstractExercise can improve morbidity and mortality in heart failure patients; however, the underlying mechanisms remain to be fully investigated. Thus, we investigated the effects of exercise on cardiac function and ventricular arrhythmias in myocardial infarction (MI) induced heart failure mice. Wild ‐type male mice underwent sham‐operation or permanent left coronary artery ligation to induce MI. MI mice were divided into a sedentary (MI‐Sed) and two intervention groups: MI‐Ex (underwent 6‐week treadmill exercise training) and MI‐βb (oral bisoprolol treatment (1 mg/kg/d) without ex ercise). Cardiac function and structure were assessed by echocardiography and histology. Exercise capacity and cardiopulmonary function was accepted as oxygen consumption at peak exercise (peak VO2). Autonomic...

Source: Physiological Reports - February 25, 2019 Category: Physiology Authors: Rujie Qin, Nobuyuki Murakoshi, DongZhu Xu, Kazuko Tajiri, Duo Feng, Endin N. Stujanna, Saori Yonebayashi, Yoshimi Nakagawa, Hitoshi Shimano, Akihiko Nogami, Akira Koike, Kazutaka Aonuma, Masaki Ieda Tags: Original Article Source Type: research